Small Animal Venipuncture, IV Catheters & Fluid Therapy

Venipuncture

The process of puncturing a vein to collect blood, administer medication, or insert an IV catheter.

Cephalic Vein

Located on the dorsal aspect of the forelimb.

Jugular Vein

Found on the neck, parallel to the trachea.

Lateral Saphenous Vein

Runs along the lateral aspect of the hindlimb.

Medial Saphenous/Femoral Vein

Used primarily in cats, located on the medial aspect of the thigh.

Restraint

Proper restraint is crucial to prevent movement, which could cause injury or unsuccessful venipuncture.

Preparation

Shave the area if necessary, and clean it with an antiseptic solution.

Needle Insertion

Choose the appropriate size needle, bevel up, and insert at a shallow angle.

Blood Collection

Collect the required amount of blood, then withdraw the needle and apply pressure to the puncture site to prevent hematoma formation.

Hematoma formation

A complication that can occur during venipuncture.

Vein collapse

A complication that can occur during venipuncture.

Improper needle placement

A complication that can occur during venipuncture.

IV Catheters

Used for the administration of fluids, medications, anesthetics, and for blood transfusions.

Over-the-needle (OTN)

Most commonly used in veterinary practice, suitable for short-term use.

Through-the-needle

Often used for central venous access.

Winged infusion sets (Butterfly Catheters)

Used for short-term access or blood collection.

Flushing

Flush with heparinized saline to ensure patency and remove any blood clots.

Fluid Therapy

Used to maintain hydration, replace lost fluids, deliver medications, and support circulatory volume in critically ill patients.

Crystalloids

Solutions that contain water, electrolytes, and possibly dextrose.

Colloids

Contain larger molecules that stay in the vascular space longer and are used for expanding blood volume.

Intravenous (IV)

Preferred for rapid fluid administration and critical cases.

Subcutaneous (SQ)

Suitable for mild dehydration and maintenance in less critical cases.

Intraperitoneal (IP)

Used when IV access is not available, often in small or neonatal animals.

Intraosseous (IO)

Used in emergencies when venous access is not possible, particularly in neonates or very small animals.

Maintenance Rate

Generally calculated as 40-60 ml/kg/day.

Replacement Rate

Based on the degree of dehydration (estimated as a percentage) multiplied by body weight in kilograms.

Ongoing Losses

Any additional fluid losses (vomiting, diarrhea) should be calculated and added to the daily fluid needs.

Clinical Signs

Monitor for signs of overhydration or underhydration.

Weight

Regular weighing can help monitor fluid balance.

Laboratory Tests

Regular blood tests to monitor electrolytes, kidney function, and blood glucose levels.

Overhydration

Can lead to pulmonary edema, pleural effusion, and heart failure.

Electrolyte Imbalances

Especially with inappropriate fluid selection or excessive administration.

Phlebitis

Inflammation of the vein, often due to prolonged catheter use or infection.